how do you work for someone without them knowing your age? Do you keep that out of your CV? How about credentials and signing your contact? Seems very strange to me.
Not only should it not matter, but it's illegal for employers to ask about it or consider it in their hiring decision, so having it right there on your CV puts them in a bit of a tight spot. I think some recruiters will actually remove that type of thing before forwarding it on to the interviewers and hiring people.
On the whole I hate the practice, but you have to consider cultural norms when doing the job-hunting dance.
There weren't a significant number of visibly-foreign immigrants in Germany till the 60s or 70s and it took a couple more decades before those were seen as anything other than 'temporary guest workers'.
The UK and France (and even more so the US and other "New World" countries) had at least a few decades head-start for culture to get around the idea of immigration.
So my only reason for including my age on the CV is because I look like I'm 24, whereas I'm pushing 31.
Photos make it easier to hire people like us :-(
My understanding is that it is not only possible not to mention your age in your CV, but even illegal for companies to ask you what your age is as part of the application process.
"So, candidate 24892 looks strong."
I don't know if I have unconscious biases, but this method was unlikely to make things less fair.